The desire to decrease and ultimately eliminate dependence on fossil fuels has stimulated research into clean and renewable ways to produce electricity for the global marketplace. Solar power is a viable option to fulfill this goal because it is a clean, carbon-free form of energy production, and there is a potentially limitless supply of solar radiation.
Technological innovations and improvements have helped to make solar power generation a feasible means for large scale power production. More specifically, the reduction in the magnitude of capital investment required and the reduction in recurring operation and maintenance costs allow solar power generation to compete with other forms of power generation.
To address the demand for solar power systems, many configurations have been designed and implemented. One such implementation is a concentrating solar power system that collects and concentrates solar energy onto an absorber wherein it is converted to heat. A thermal carrier, for example a fluid such as an oil or molten salt, can be used to transport the heat, for example by pumping, to a power conversion system. The power conversion system utilizes the heat to produce electricity that can be fed into an electrical grid or other system. The thermal carrier is cycled indefinitely between the absorber and the power conversion system.
A significant impediment to wide-spread implementation of solar power systems is the transient nature of solar energy and the temporal mismatch between peak solar flux and consumer power demands. Accordingly, a need exists for a solar power generation system with the ability to store the collected energy so that electrical energy production can be optimized to follow periods of high power demand. Advanced concentrating solar power systems can meet this need by oversizing the collection portion of the system relative to the power block, and providing a means to store the thermal fluid at elevated temperature, for example an insulated tank holding molten salt.
However, the current generation of heat transfer fluids is not ideal as storage media. Molten salt, the current state of the art material, and other fluids are limited to temperatures below approximately 600° C. Additionally, molten salts are corrosive and store energy only as sensible heat, resulting in a relatively low energy storage density. These attributes drive storage costs higher and are incompatible with high-efficiency, high-temperature power cycles with the potential to reduce the cost of the electricity produced, such as Brayton cycles.